Problem: Ishaan ate 3 slices of pizza. Umaima ate 5 slices. If there were 5 slices remaining, what fraction of the pizza was eaten?
$\text{fraction of pizza eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ Since they ate 8 slices of pizza with 5 slices remaining, they must have begun with 13 slices. They ate ${8}$ out of $13$ slices. They ate $\dfrac{8}{13}$ of the pizza.